Steering column for a motor vehicle

Abstract

A steering column for a motor vehicle, with a steering shaft, including a damping element for damping vibrations transmitted across the steering shaft. The damping element includes an inner damper part, rotatable about a longitudinal center axis, whose outer circumferential contour comprises several outer elevations, spaced apart in the circumferential direction about the longitudinal center axis and projecting radially outwardly, between which are located outer indentations of the outer circumferential contour of the inner damper part. An outer damper part encompasses the inner damper part and is rotatable about the longitudinal center axis, the inner circumferential contour of which comprises several inner elevations, spaced apart from one another in the circumferential direction about the longitudinal center axis and radially projecting inwardly, between which inner indentations of the inner circumferential contour are located. An elastomeric damping material is disposed between the inner damper part and the outer damper part.

1 . A steering column for a motor vehicle, with a steering shaft, wherein a damping element is provided for damping vibrations transmitted via the steering shaft, and wherein the damping element comprises an inner damper part, rotatable about a longitudinal center axis, whose outer circumferential contour, viewed in cross section through the damping element, comprises several outer elevations, spaced apart from one another in the circumferential direction about the longitudinal center axis and radially projecting outwardly, between which outer indentations of the outer circumferential contour of the inner damper part are located, an outer damper part encompassing the inner damper part and rotatable about the longitudinal center axis, the outer damper part having an the inner circumferential contour, viewed in cross section through the damping element, comprising several inner elevations, spaced apart from one another in the circumferential direction about the longitudinal center axis of the rearward steering shaft segment and projecting radially inwardly, between which inner indentations are located of the inner circumferential contour of the outer damper part, and an elastomeric damping material disposed between the inner damper part and the outer damper part, an angular range α, over which a particular outer elevation of the outer circumferential contour of the inner damper part extends in the circumferential direction about the longitudinal center axis, is smaller than a particular angular range β over which a particular outer indentation of the outer circumferential contour of the inner damper part extends in the circumferential direction about the longitudinal center axis. 
     
     
         2 . The steering column as in  claim 1 , wherein the particular angular range β, over which a particular outer indentation of the outer circumferential contour of the inner damper part extends in the circumferential direction about the longitudinal center axis, is greater by 25% to 50% than the angular range α over which a particular outer elevation of the outer circumferential contour of the inner damper part extends in the circumferential direction about the longitudinal center axis. 
     
     
         3 . The steering column as in  claim 1 , wherein the outer elevations of the outer circumferential contour of the inner damper part project into the inner indentations of the inner circumferential contour of the outer damper part. 
     
     
         4 . The steering column as in  claim 1 , wherein, viewed in cross section through the damping element, the outer circumferential contour of the inner damper part comprises curved first segments, which form the outer elevations, wherein the outer elevations formed by the first segments are inscribed in a first radius of curvature, and second segments which are located between the first segments in the regions of the outer indentations and which include bases having a second radius of curvature that is greater than the first radius of curvature or which extend in straight lines. 
     
     
         5 . The steering column as in  claim 4 , wherein the second radius of curvature is more than twice as large as the first radius of curvature. 
     
     
         6 . The steering column as in  claim 1 , wherein the outer indentations include bases which, viewed in cross section through the damping element, have an outwardly convexly curved form or extend in straight lines. 
     
     
         7 . The steering column as in  claim 4 , wherein the first and the second radii of curvature extend about centers located within the outer circumferential contour of the inner damper part. 
     
     
         8 . The steering column as in  claim 4 , wherein the inner damper part is formed by a sleeve and the first radius of curvature is the 0.8-fold to 1.2-fold of the value of the wall thickness of this sleeve measured in the proximity of one of the outer indentations. 
     
     
         9 . The steering column as in  claim 1 , wherein the radius of a greatest circumscribed circle of the inner damper part, which extends through the radially outermost points of the outer elevations, is greater by 10% to 30% than the radius of a smallest circumscribed circle of the inner damper part which extends through the radially innermost points of the outer indentations. 
     
     
         10 . The steering column as in  claim 1 , wherein the outer damper part has an outer circumferential contour, deviating, viewed in cross section through the damping element, from the circular form, with which it is in engagement with the inner circumferential contour, deviating, viewed in cross section through the damping element, from the circular form, of a sleeve-shaped segment of a first shaft part of the steering shaft under form closure with respect to the rotational direction about the longitudinal center axis, wherein the first shaft part preferably projects from the damping element in the direction of the longitudinal center axis. 
     
     
         11 . The steering column as in  claim 1 , wherein the inner damper part has an inner circumferential contour deviating, viewed in cross section through the damping element, from the circular form, with which it is in engagement with the outer circumferential contour, deviating, viewed in cross section through the damping element, from the circular form, of a segment of a second shaft part of the steering shaft under form closure with respect to the rotational direction about the longitudinal center axis, wherein the second shaft part preferably projects from the damping element in the direction of the longitudinal center axis. 
     
     
         12 . The steering column as in  claim 11 , wherein the second shaft part is connected non-rotatably with a third shaft part, wherein the third shaft part preferably projects from the second shaft part in the direction of the longitudinal center axis. 
     
     
         13 . The steering column as in  claim 1 , wherein the steering shaft comprises a rearward steering shaft segment, which extends in a straight line and is rotatable about the longitudinal center axis and on which is mountable at a rearward end a steering wheel, and at least one further steering shaft segment connected with the rearward steering shaft segment via a universal joint which comprises a rearward joint fork, a front joint fork and a joint cross connecting the rearward joint fork and the front joint fork, wherein the damping element is integrated into the rearward steering shaft segment, wherein the rearward steering shaft segment is rotatably supported via at least one front pivot bearing which is located between the damping element and the universal joint, and the rearward steering shaft segment is rotatably supported at least via a rearward pivot bearing located between the damping element and the rearward end of the rearward steering shaft segment. 
     
     
         14 . The steering column as in  claim 13 , wherein the steering column comprises an electric power assistance unit, wherein the damping element is disposed between the rearward end of the rearward steering shaft segment and the electric power assistance unit. 
     
     
         15 . The steering column as in  claim 13 , wherein the steering column is at least adjustable in its length, wherein the rearward steering shaft segment comprises two shaft parts that are telescopable with respect to one another. 
     
     
         16 . The steering column as in  claim 4 , wherein the second radius of curvature is more than three times as large as the first radius of curvature.